<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../../../vue.js"></script>
  <style>
    .public {
      width: 100px;
      height: 100px;
    }

    .active {
      background: red;
    }

    .noActive {
      background-color: yellowgreen;
    }

    .red {
      color: red;
    }

    .bold {
      font-weight: bold;
    }

    .italic {
      font-style: italic;
    }
  </style>
</head>

<body>
  <div id="app">
    <!-- 1.值是一个字符串,类名一般只有一个,并且不确定是哪一个 -->
    <div class="public" :class="isActive?'active':'noActive'">box1</div>
    <div class="public" :class="fontColorClass">box2</div>

    <!-- 2.值是一个对象,对象的key都是需要的class名称,值是布尔值,通过布尔值来控制当前类是否使用
           用法:类固定,但是不确定用不用 -->
    <div class="public" :class="box3Class">box3</div>
    <div class="public" :class="{red:isRed,bold:isBold,italic:isItalic}">box4</div>
    <!-- 3.动态class:值是一个数组
        用法:类型个数不固定,可以操作数组,对类名进行增删改 -->
    <div class="public" :class="classArr">box5</div>
  </div>
  <script>
    Vue.config.productionTip = false
    const vm = new Vue({
      el: "#app",
      data: {
        isActive: true,
        fontColorClass: "red",
        box3class: {
          red: true,
          bold: true,
          italic: true,
        },
        isRed: true,
        isBold: false,
        isItalic: true,
        classArr: ['red', 'italic']
      }
    });
  </script>
</body>

</html>